Ignition controlling means



Aug. 20, 19 6. F. B. AUBERT IGNITION CQNTliOLLING MEANS Filed May 13,1943 2 Sheets-Sheet 1 FIG.\

INVENTOR 3M 6. W BY MATTORNEY 20, 1945. F. B. AUBERT IGNITIONCONTROLLING MEANS Filed May 13, 1943 FIG. 3

I 2 Sheets-Sheet 2 INVENTOR 27/114, 6.

1 MA TORN Y Patented Aug. 20, 1946 UNITED STATES PATENT OFFlCE IGNITIONCONTROLLING MEANS Fred B. Aubert, Grosse Pointe, Mich. Application May13, 1943, Serial No. 486,829

9 Claims.

This invention relates to new and useful improvements in gaseous-fuelburning apparatus and more particularly to means for controlling theoperation of a burner igniting means.

An object of the invention is to provide a novel apparatus forcontrolling the operation of a gaseous fuel burner and its ignitingmeans.

Another object is to provide a safety feature for gaseous fuel burneroperation in the event of leakage of gas to the burner or failure of theburner gas supply valve to close.

Another object is to provide means by which the ignition means will beoperated for a period following operation to close the gas supply valve.

The invention consists in the novel arrangement and cooperative relationof parts in the apparatus, as will be more fully described hereinafterand the novelty of which will be particularly pointed out and distinctlyclaimed.

In the accompanying drawings, to be taken as a part of thisspecification, there are fully and clearly shown several preferredembodiments of the invention, in which drawings:

Figure 1 is a diagrammatic view of a gaseous fuel burning apparatus withits control system;

Fig. 2 is a detail diagrammatic view showing a different arrangement ofcertain switch operating cams forming part of the controlling means ofFig. 1 and providing a different sequence of switch operation;

Fig. 3 is a diagrammatic view similar to that of Fig. 1 but having thecontrolling means entirely operated by relays, and

Fig. 4 is a diagrammatic view of a burner apparatus embodying theinvention and having a manually operable fuel controlling valve.

Referring to the drawings by characters of reference there is in Fig. 1a gaseous fuel burner I having a fuel supply pipe or conduit 2controlled by an automatic fuel supply valve 3, preferably anelectrically operated or solenoid valve. The valve 3 has a valve member4 which is moved to open position by the magnetic force of the usualsolenoid coil 5 and which is urged toward closed position by gravity orspring force upon deenergization of the coil 5. The circuit of the valvecoil 5 is controlled by a relay switch 6 having a relay coil 1 andnormally urged to open position by a spring 8, from the switch 6 a wire9 leads to one end of the coil 5 which has its other end connected by awire I0 to one of the main line wires I I connected to a source ofalternating current supply. The other side of the switch 6 is connectedby a wire I2 to one end of a wire I2 which is connected at its other end2 to one side of a normally open main switch I3 having a relay coil I4and havin its other side connected by a Wire I5 to one end of a wire 45which is connected at its other end to the other main line wire [6connected to the source of current. From the junction of wire I2 andwire I2--, a wire I! connects to one end of a wire H which has its otherend connected to one terminal of the primary coil 48 of the ignitioncontrolling transformer IS, the other terminal of the transformerprimary being connected to the line wire II. The transformer secondaryhas a coil 20 mid-tapped to ground, as at 2|, and having it endsconnected by wires 22, 23 to the filament cathode 24 of an electron tube25, having an anode 26 and a control grid 21. A transformer secondarycoil 28 is connected by a wire 29 to the intermediate turn of theprimary coil 30 of an air core radio frequency transformer 3|. A wire 32connects the positive terminal of the coil 38 to the plate or anode 2B.The other terminal of the primar coil 30 is connected to the grid 21 bya wire 33 in which there is positioned a grid controlling condenser 34.A grid leak resistor 35 is positioned in a wire 38 which connects thegrid 21 to the other side of the coil 28. A by-pass condenser 31 isconnected across the terminals of the coil 28 and has a value inaccordance with the frequency at which the circuit is to be operated.The middle tap of the coil 28 is connected to the wire 36 between theresistor 35 and coil 28 by a wire 38, Balancing condensers 39, Ml areconnected between the midtap of coil 28 and the cathode lead wires 22,23, the condensers 39, All and 34 and the resistor 35 having such valuesthat the tube 25 is oscillated at predetermined radio frequency ofhundreds of kilocycles. The secondary coil 4| of the ignitiontransformer 3| has its positive terminal connected by a conductor 42 toa spark electrode 43 which is cooperable with the burner I which isconnected to ground, as at 44. The other end of the secondary coil IIand the corresponding end of a coupling con .45 are connected togetherand to ground, as at 46. The coil 55 has its positive terminal connectedby a wire 41 to branch wires 41 and 41 connected respectively to thespace discharge or gas ionizing electrodes 48, 49 of gas tube warpswitches 50, 5! respectively. Each has a sealed glass envelope chargedwith an inert gas or combination of gases at a predetermined pressuresuch, for example, as in the Sheldon type FSi-NA gas tube warp switchused for fluorescent tube excitation. The switch 50 has normally closedcontacts 52, $3 of 3 which the movable contact 53 is carried by abimetal blade or strip 54. The switch 5! has normally open contacts 55,56, of which the contact-56 is carried by a bimetal blade or strip 51.The bimetal strips 54, 51 are connected together by a wire 58 which isconnected to ground, as at 59, through a condenser 60. The envelopes ofswitches 50 and 5| are charged with difierent gases or gas mixtures orat difierent pressures, as is well understood in the art, such that thegas in the tube'or envelope of switch 56 will ionize sufliciently tooperatively heat the arm 54 at a higher voltage on the electrode 48 thanthe voltage necessary on the electrode 49 to operatively heat the arm 51of the tube 51. The fixed contact 55 is connected by a wire 6| to oneterminal of the relay coil 1, having its other terminal connected by awire 62 to one terminal of the secondary coil 63 of a step down lowvoltage transformer 64 having it primary coil 65 connected across theline wires (6 and H by wires .66, 61. From the transformer secondarycoil 63 and wire 62, a wire 63 connects to one end of a wire 68" whichhas its other end connected to one terminal of the relay coil l4 havingits other terminal connected by a lead wire 69 to one end of a wire (ithaving its other end connected to a main or dominant switch 10 such as aroom thermostat. From the other side of the switch 10 a wire H connectsback to the transformer secondary coil 63.

Operated by the relay coil (4 is a timer motor relay switch 12 havingnormally closed contacts 13 and normally opened contacts 14. The switcharmsl5 of the switch 12 is connected by a wire 16 to the junction of thewire 68 with the wire 68 leading from the transformer secondary coil 63.The arm is mechanically connected by a link 17 to the operating arm 18of the main relay switch [3 so that the switches 12 and I3 are movablein unison. The switch 72 is in series-parallel circuit with a timermotor snap switch 79 having normally closed contacts 80, of which thefixed contact is connected by a wire 8! to the fixed one of switchcontacts 74 and having normally opened contacts 82, of which the fixedcontact is connected by a wire 83 to the fixed one of contacts 73. Theswitch operating arm 84 having the movable contacts of switch! 9 isconnected by a wire 85 to one terminal of a timer motor 86 having itsother terminal connected by a wire 81 back to the transformer secondarycoil 63. The timer motor 86 rotates a drive shaft 88 through reductiongearing 89. Fixed on the shaft 88 there is an operating cam wheel 90having a cam 9| cooperable with a follower 92 mounted on the switch.operating arm 84. The cam Si is normally positioned as shown in Fig. 1in which it is engaging the follower 92 to hold the switch contacts 80in closed position. The shaft is rotated at a speed of about onerevolution in three minutes and the cam 9| is designed so thatsubstantially immediately after starting of rotation of the wheel 90,the follower 92 will drop off the cam 9|, so that the snap switchcontacts 82 will be closed (preparatory to restarting the motor 86 afterthe burner I has been stopped) and the cotnact 80 will be opened to stopthe motor 86. It may be noted that because the wheel 90 takes aboutthree minutes for complete rotation, sub stantially this time willelapse after the motor 86 is again started by another circuit hereafterdescribed and before the snap switch 19 is again moved back to theposition of Fig. 1 with its contacts 80 in closed position. Also mountedon the shaft 88 there is a cam wheel 93 having a cam 94 cooperable withthe flexible blade of a normally open ignition controlling cam switch96. The switch 95 has its fixed contact connected by a wire 91 to thejunction of the wire 15 with the wire l5 and has its movable contactconnected by a wire 98 to th junction of the wire I! with the wire 1?.The cam 54 is so designed that it engages the switch arm 95substantially adjacent the termination of a revolution from its startingposition and closes the switch 96 for a short period prior to theopening of snap switch contacts 82, the cam 94 moving on into theposition of Fig. l at the time of opening of the switch contacts 82.

The operation of the apparatus or system of Fig. l is as follows. Whenthe dominant switch or room thermostat it is closed in calling for heator operation of the burner I, the relay coil I4 will be energized,assuming that the main line circuit of wires II and (6 has beencompleted. The circuit of the relay coil is as follows, from thetransformer secondary coil 63 through lead wire 68 and wire 68 to thecoil [4 and thence through wire 69 and 69 to the closed switch 10 andback to the other terminal of transformer coil 63 through wire H. Thecoil [4 will attract the arms 15 and 18, thereby to close the main relayswitch l3 and to operate the timer motor relay switch 12, breakingcircuit at the contacts 13 and making circuit at the contacts 14. Thisrelay switch operation will cause the substantially simultaneousenergization of the timer motor 86 through the now closed contacts 14and of the ignition controlling transformer l9 through the now closedswitch [3. The circuit through the closed switch [3 will be as follows,from the main line wire I 6 through the wire l5 and the wire l5 to thestationary contact of the switch [3 and thence through its switch arm18, lead wires I2"; I! and ll to one terminal of the primary coil L8 ofthe transformer l9 and thence from the other terminal of coil [8 back tothe source of current supply through the main line wire II. The circuitof the motor 86 which was completed by a of the snap switch 79 andthence through the snap switch arm 84 and wire 85 to one terminal of themotor 86, and from the other terminal of the motor 85 through wire 8!back to the other terminal of the transformer coil 63. The energizationof motor 86 will rotate th cam wheels and 93 in a clockwise direction,as shown by the arrows, and shortly after the start of rotation of thewheel 99, the cam 9| will move out of holding relation to the follower92 so that the switch arm 84 will operate with a snap action to open thecontacts 80 and to close the contacts 82, thereby stopping the timermotor 86. This operation of closing the contacts 82 is preparatory toreenergization of the motor 86 upon reclosure of the timer relay switchcontacts 13. The wheel 93 will not perform any function during thisinitial operation of the motor 86.

When the ignition controlling transformer coil I8 is energized byclosure of the switch I3, the network of the electron tube 25 will beenergized to oscillate the tube 25 at predetermined radio frequency, asabove noted. There will thus be set up in the coil 4| of the ignitiontransformer 3|, due to the spacing of the coils 30 and 4| and the ratioof their coil tums. which may be one to ten, a radio frequency voltagepreferably above 50,000 v. and at micro amperage. This radio frequencyvoltage at micro amperage is supplied by the conductor 42 to the sparkelectrode 43, with the result that there will be a discharge of flowingspark streams from the electrode 43 to the burner I. It is preferable toemploy a transformer 3| which will provide a voltage of say 250,000 v.at the electrode 43, so that the discharging spark streams will be ofconsiderabl length. Assuming that the electrode 43 is properlypositioned relative to the burner I, that is, such that the burner I isintermediate the length of the discharging spark streams from theelectrode 43, then the frequency and voltage in the coil 4| will be suchthat the coupling coil 45 will deliver frequency and voltage ofsufficient values to the space discharge electrode 49 to ionize the gain the tube 5| and create suificient heat on the bimetal switch actuator57 to close the contacts 55, 56. This will result in the energization ofthe valve controlling relay coil I by the following circuit, from thetransformer secondary coil 63 through wire 62 to the coil I and thencethrough wire 6|, closed contacts 55, 56, wire 58, closed contacts 52, 53of warp switch 50, wires 58 and 69 to the dominant switch 10 and thencethrough wire II back .to the transformer coil 63. Energization of coil Iwill close the contacts of the valve relay switch 6, thereby energizingthe solenoid valve coil 5 as follows, from main line wire I6 throughwire I5 and wire I5 to the closed switch I3 and thence through switcharm I8, wire I2 and wire I2 to the closed relay switch 6 and thencethrough wire 9 to the coil 5 and thence through wire I0 to the main linewire I I. Current flow through the coil 5 will open and hold Open thevalve member 4 of the gas valve 3 so that the fuel will be supplied tothe burner I to be ignited by the spark streams discharging from theelectrode 43. The warp switch 5| serves not only as the control switchfor operating the relay switch 6 upon the occurrence of ignition butalso serves as a safety switch to prevent operation of the gas valve 3in the event of short circuitin of the conductor 42 or electrode 43, orin the event of a positioning of the electrode 43 too close to theburner I, such that the length of the spark streams is very short. Ineither of these events of short circuiting or short spark streams, thevalues of the voltage and frequency applied to the discharge electrode49 will be insufficient to ionize the gas sufiiciently in the tube 5| tocause resulting closure of the switch contacts 55, 56. The gas tube warpswitch 50 is a safety means to prevent opening of the gas valve 3 in theevent of spacing of the electrode 43 so far away from the burner I thatthe discharged spark streams from the electrode 43 will not impinge onthe burner in bunched spark streams. When the electrode 43 is sopositioned at too great a distance from the burner I, then the values ofthe voltage and frequency applied to the discharge electrode 48 will beincreased and be sufficient to ionize the gas in the tube 50sufficiently to heat the bimetal actuator 54 which will thereforeseparate the contacts 52, 53 so as to break the circuit of the relaycoil I.

When it is desired to stop operation of the burner I, the dominantswitch I0 is operated to open position which will break the circuits ofrelay coils I and I4 which are in parallel with each other, but both ofwhich are in series circuit with the switch "III. Deenergization ofcoils .6 I and I4 will permit their respective switches 6 and I3 whichare in series with the valve coil 5 to move to open position therebydeenergizing the valve coil 5 and accordingly the valve member 4 shouldmove to closed position and cut ofi further flow of fuel to the burnerI. In order to avoid the possibility of explosion or of other hazard, ifthere is a leakage of gas at the valve 4 after the flame at the burner Ihas been extinguished, a safety means is provided for igniting the gasescaping at the burner I. Opening of the switch III will break thecircuit of the relay coil I4, thereby permitting the switch arm I5 toclose the switch contacts I3 of the timer motor relay switch I2 so thatthe timer motor 86 is reenergized through the following circuit, fromthe transformer secondary coil 63 through wires 68, I6 and arm 15 to theclosed contacts I3 and thence through lead wire 83 to the closed snapswitch contacts 82 and thence through snap switch arm 84 and wire 85 tothe motor 86 from which the wire 81 completes the circuit back to thetransformer coil 63. Upon this reenergization of motor 86, the cam wheel93 will again be rotated in its clockwise direction and when the abovementioned predetermined time period of say about three minutes haselapsed, then the cam 94 will engage the switch arm 95 and close the camswitch 96. This will establish a circuit to the ignition controllingtransformerprimary coil I8 to energize the ignition transformer 3| andcause the discharge of bunched spark streams from the electrode 43 tothe burner I, the circuit of switch 96 being as follows, from the mainline wire I6 through wires I5 and 91 to the closed switch 96 and thencethrough wires 98 and II to one terminal of the coil I8 which, as abovenoted, has its other terminal connected to the main line wire II. Theswitch 96 will be held closed by the cam 94 for a short time period ofsay 5 or 10 seconds duration but sufficient to assure the ignition ofgas leakage at the burner I. When the cam 94 leaves the switch arm 95,the arm 95, which is preferably resilient,

'- will snap the switch 96 to open position, thereby breaking theignition controlling circuit through the transformer primary coil I8.Subsequent to this opening of switch 96 by the cam 94, the cam 9| willbe rotated to engage the follower 92 to operate th snap switch I9 tobreak the timer motor circuit at the contacts 82 and to remake apreparatory circuit at the contacts 86, the opening of the switchcontacts 82 serving to stop the timer motor 86 in position for the startof a new cycle or period of burner operation which will be establishedby the closure of the dominant switch I0.

Referring to Fig. 2, the cam wheels and 63 are provided with cams ofdifferent form and relative position from that of the cams 9| and 94 ofFig. 1. In Fig. 2, the wheel 90 has a cam I98 which, as in the case ofthe cam 9|, cooperates with the follower 92, serving to position thecontacts 89 of the snap switch I9 in closed position for the start of aburner cycle. This cam I 26 ha an extending length of cam surface so asto maintain the timer motor 86 in operation for a substantial period oftime following closure of the dominant switch I6. The cam wheel 93 has acam IOI cooperable with the switch blade of the switch 96. The cam IIIIis positioned when the timer motor is stopped by the opening of switchcontacts 92, in a position, as in Fig. 2, such that after the timermotor 86 has been started at the beginning of burner operation, the

cam I will engage and close the switch 98 during the time period of theholding of switch contacts 80 in closed position by the cam I60. The camit! therefore serves while the main relay switch 13 is closed, to closea parallel circuit to the ignition controlling transformer secondarycoil 18, see Figs. 1 and 2, as follows: From wire 15* to wire 91 andthrough the now closed switch 96 and its arm 95 to the wire 88 andthence through wire 11 to the coil 18. While the switch 96 is heldclosed by the cam I!!! so that ignition will remain on when switch 13 isopened, the cam I00 moves out of holding engagement with the follower 92so that the nap switch 19 is actuated to stop the timer motor 86 bybreaking the timer motor circuit at contacts 80 and to close the timermotor preparatory circuit at the contacts 82. The cam IBI has a camsurface of suificient length so that the switch 96 is maintained closedwhen the timer motor 85 is stopped by the opening of the switch contacts80. It will therefore be apparent that when the dominant switch H! iopened at the end of a heating period that the ignition controllingtransformer secondary coil i8 will not be deenergized, the circuit tothe same being maintained at switch 96 during the heating period and fora time period thereafter. Ignition at the electrode 43 will thereforecontinue after the solenoid valve coil has been deenergized. The timeperiod or duration of time during which the switch 95 is maintainedclosed after the burner is stopped can, of course, be determined by therate of rotation of the shaft 88 and the length of the cam surface ofthe cam NH. The speed of rotation and length of cam surface ispreferably such that ignition will be kept on at the electrode 43 for aperiod of say three minutes following the opening of the dominant switch10, so that there will be ignition of any gas leakage through the closedvalve member 4 when the leakage is of sufiicient value to provide acombustible mixture at the burner I. The foregoing partial descriptionof the operation of the cams of Fig. 2, when taken in connection withthe complete description of Fig. 1, will make obvious the completeoperation of the system when provided with the cams as shown in Fig. 2.

Referring to the apparatus of Fig. 3 there is a gas burner 200 which iselectrically grounded, a at 201, and which has a fuel supply pipe orconduit 292 controlled by an automatic gas valve 9.93, preferably anelectrically operated or solenoid valve. The valve 203 has a valvemember 264 and an electric operating coil 205. The coil 285 i controlledby a relay switch 206 and by a main relay switch 201 which are in seriecircuit as follows, from the main line wire 298 through wire 209 to thefixed contact of the switch 2133 and thence from its movable contactthrough wire 210 to one terminal of the coil 295 and from the other coilterminal via wire 2| l and 2| I to the movable contact of relay switch201 and thence from the fixed contact of switch 201 by a lead wire 212to the other main line wire 213. The coil 2 of the main relay switch 201is controlled by a dominant switch 215 which, as in Fig. 1, may be aroom thermostat, the circuit of this switch and coil being as follows,from the secondary coil 2l6 of a. step down low voltage transformer 2| 1via a wire 2| 8 to one end of a wire 2l8 having its other end connectedto the coil 2 l4 and thence via a wire 219 to one contact of switch 2|5having its other contact connected to a wire 220 leading to a wire 220which leads back to the other end of the transformer coil U6. Thetransformer 2H has a primaly coil 22! connected by wires 222 and 223 tothe main line wires 213 and 208 respectively. The relay coil 224 ofrelay switch 206 is also supplied with current from the coil 2H5 and, ain Fig 1, has in its circuit a normally open gastube warp switch 225 anda normally closed gas tube warp switch 226. The switch 225 has a bimetalactuator 221 normally holding a switch contact 228 spaced from itscooperating fixed contact 229. The switch 226 as a. bimetal actuator 230normally holding its contact 23l in closed circuit making position withthe fixed contact 232. The switches 225, 226 in this form of theinvention of Fig. 3 contain the same charge of ga or gas mixture and atthe same pressure as distinguished from the different gas charges in theswitches 50, 51.

The ignition means of Fig. 3 is the same as that heretofore describedand shown in Fig. l and therefore the reference characters applied toFig. 1, but with the suifix a," designate like parts in the ignitionmeans of Fig. 3. Since the switche 225, 226 are of like characteristics,the values of voltage and frequency at which they re spond arecontrolled by condensers 233, 234, preferably having capacities of .001microfarad and .01 microfarad respectively. The condenser 233 isconnected in a wire 235 leading from the coupling coil conductor or wire41 to the discharge electrode 48 of switch 226. The condenser 234 ispositioned in a wire 236 leading from the wire 41 to the discchargeelectrode 49 of switch 225. The ignition means of Fig. 3 is, however,controlled by a relay switch 231 in the filament cathode circu t andinterposed in the wire 22 leading to the cathode from the 6 v. coil 20*.The switch 231 corresponds to the switch 96 of Figs. 1 and 2. The relaycoil 238 of the switch 231 has its energizing circuit controlled by themain relay switch 231 as follows. The relay coil 23!; of the switch 231is supplied with current from the main line wire 208 through a half waverectifier 239 and has its energizing circuit controlled by the mainrelay switch 261. The energizing circuit for the coil 238 i as follows,from the main line wire 208 through a wire 240 to the rectifier 239 andthence via a wire 24! to the coil 238 and thence via wir 242 to thejunction of the wire 2 with the wire 2| l leading to the movable contactof the switch 201. In shunt with the coil 238 there is a condenser 243connected across the wires 24l and 242. Connected between the wire 241and the condenser 243 there is a resistor 2M cooperable with thecondenser to determine the time period of condenser discharge to thecoil 238 to hold switch 231 closed following the opening of the switch201.

The operation of this apparatus of Fig. 3 is as follows. When thedominant switch 2 I5 is closed, the relay coil 214 will be energized topull switch 201 to closed position, thereby completing the energizingcircuit of the relay coil 238 so that the ignition controlling relayswitch 231 is closed. The circuit of coil 238 is as follows: From linewire 208 to wir 240, through the half wave rectifier 239, to wire 24!and through coil 238 and wires 242, 2| I to closed switch 201 and thencethrough wire 2 l2 to the other line wire 2 l 3. The closure of switch231 energizes the circuit of the electron tube 25 to provide the radiofrequency high voltage microamperage current supply to the sparkelectrode 43", as described in connection with Fig. 1. Upon theoccurrence of a proper discharge of the bunched spark streams from theelectrode 43" to the burner 260. as described in connection with Fig. l,the warp switch gas tube 225 will be energized to close the switchcontacts 228, 229, thus completing the circuit of the ga valve relaycoil 224 from transformer coil 216 via wire 218 to wire 224 to the coil224, thence through Wire 224 the closed switch 225, wire 225 closedswitch 226 to the wire 226 and thence through wire 225 back to thetransformer coil 216, so that the gas valve relay switch 208 will beclosed. Upon closure of switch 236 the circuit of the coil 205 will becompleted as above described, thereby opening the gas valve 203 tosupply gas to the burner 200 for ignition by the discharging sparkstream from the spark electrode 43. The switches 225 and 226 serve assafety meam to prevent opening of valve 263 as was described forswitches 59 and 51.

When the dominant switch 215 i opened for any reason-the circuit of thmain relay switch coil 214 will be broken so that the main relay switchwill be opened, thereb deenergizing the valve coil 205 and breaking theenergizing circuit of the ignition controlling relay coil 238. The relayswitch 231 will, however, remain closed so that ignition will bemaintained in order to provide ignition for any gas which may leak pastthe valve 284 in suflicient volum to provide a combustible mixture atthe burner 208. Ignition will be maintained for a predetermined periodof time following deenergization of coil 285 for movement of valvemember 204 toward closed position. the time period being determined bythe capacity of the condenser 243 and the value of the resistor 244which determines the time period to drain the condenser. When thedischarge from the condenser 243 is no longer capable of energizing thecoil 238 sufiiciently to hold the switch 231 in closed position, thenthe switch 231 will move to open position, thereby breaking the filamentcathode circuit 22'; 23* to deenergize the electron tube 25* and stopfurther operation of the ignition means.

Referring to Fig. 4, an apparatus or system is shown which utilizes amanually operable gas valve in lieu of the automati valves of Figs. 1and 3 and which util zes any of the well known or conventional electricignition means, although it will be apparent that the ignition means andthe ignition responsive safety means of Figs. 1 and 3 might be employed.In this Fig. 4 the gaseous fuel burner 33!! is supplied with gaseousfuel through a pipe or conduit 301, the flow of fuel being controlled bya manually operable valve 382 having a valve member 353 cooperable witha valve port 334. The val e member 323 is normally urged toward closedposition by a helical coil compression spring 305 acting on the valvestem 338. The valve member 333 is movable to open position b a manuallyoperable cam member 301, which may be pivotally secured to the valvestem and have its cam surface bearing on the valve bonnet, for example.Secured to the stem 336 and electrically insulated therefrom, there is aswitch am 308 having a flexible resilient portion 309 carrying contacts310, 311 insulated from each other. The contact 310 is engageable witha. fixed contact 312 during movement of the valve member 353 to closedposition, the valve member 333 being permitted to have continuedmovement to its seat after engagement of these contacts by reason of theflexible arm portion 333. The contact 310 is connected by a lead wire313 to one terminal of a heater coil 314 which has its other terminalconnected by a wire 314 to the main line wire 315 leading from a sourceof current supply. The fixed contact 312 is connected by a wire 3"; to

the other main line wire 3!! so that when the contacts 310 and 312 areengaged, then the coil 314 will be energized. The coil SM is in heatexchange relation and operable to heat a thermostatic element 318,preferably a bimetal operating arm or blade rigidly secured to a base atone end and at its other end carrying a switch contact 319. The blade318, when cold. or when it has cooled following deenergizat-ion of coil314, warps to the right facing Fig. 4 so as to move the contact 3i9 intoengagement with a fixed contact 32!). thereby closing the circuit of theprimary coil 321 of an ignition transformer 322, the circuit being asfollows, from the main line wire 315 through a wire 323 to the blade 518and contact 319 and from the contact 320 through a wire 324 to a wire324 connected to one terminal of the coil 321 and thence via a wire 325to the main line wire 311 The secondary coil 325 of the ignitiontransformer is connected by wires 32?, 3.28 to the spark ignitionelectrodes 329 positioned in cooperative relation with the burner 3.03to ignite the gas discharging therefrom when the valve member 383 isopened. The contact 31 1 is cooperable with a contact 330 and isengageable therewith upon the valve member 303 reaching substantiallyfull open position by operation of the cam member 397. When the contacts31 1 and 330 are engaged with each other, a circuit will be establishedto the transformer primar coil 321 as follows, from main line wire 315through wire 331 to contact 31 1 and from contact 330 through wire 332to the wire 324 leading to the coil 321 and thence via wire 325 to themain line wire 3 11.

The operation of this apparatus of Fig. 4 is as follows. During thestand-by period when no heat is desired from the burner 300, so that thevalve member 333 is closed, the coil 314 will be heated by reason ofclosure of contacts 310, 312 so that the transformer 322 will bedeenergized by reason of th open circuit at the contacts 319. 320. Whenthe cam 30! is manually operated to open the valve 323, the contact 311will engage the contact 3311, thereby closing the circuit to thetransformer 32?. as above described, so that ignition spark at theelectrodes 329 will ignite the gas at the burner 300. When it is desiredto stop further operation of the burner 38!), the cam 38'! is moved tothe position of Fig. 4 which will break the circuit to the transformer322 at the contacts 311, 339 but the circuit to the transformer primarycoil 321 will b maintained through the closed warp switch contacts 359.32 so that ignition sparks at the electrode 329 will continue andignition will be maintained. Therefore, if the closing movement of thevalve 303 extin uished the flame at the burner 330, but the valve member303 failed to close off gas flow through the port 304 to the pipe 391 sothat gas flow of ignitable proportions continued to feed to the burner3B3, then the continued ignition will i nite the gas leakage to theburner 369. The period of continued ignition is controlled by the heatinof the blade 318, the

' coil 314 being energized by closure of contacts 310,

3l2 as the valve member 353 moved toward closed position. Therefore, apredetermined time after movement of valve member 303 toward closedposition and closure of contacts 310, 312, the blade 318 will have beenheated sufliciently b the coil 314 to move contact 31!! away fromcontact 320 and thereby break the circuit to the transformer primarycoil 321. Thi predetermined time period for breaking of circuit atcontacts 319, 320 is sufficient to assure that ignition will bemaintained on long enough to ignite any leakage mixture at the burner300 following extinguishment of the flame by closing movement of thevalve member 303.

From the foregoing it will be apparent that there is provided a safetymeans to eliminate the hazard of gas leakage following presumed closureof the burner controlling gas valve and that the danger of collecting anexplosive gas mixture in the burner combustion chamber is overcome.

What is claimed and is desired to be secured by Letters Patent of theUnited States is:

l. A burner control apparatus comprising a gaseous fuel burner, means tosupply fuel to said burner, an electrically operable valve controllingthe supply of fuel through said means to said burner and normally biasedto closed position, a spark discharge electrode for igniting the fuelsupplied to said burner, means including a pair of relay switches inseries circuit and controlling the energization of said valve, means tosupply electrical energy to said electrode, means including one of saidrelay switches controlling the operation of said energy supply means,means including a main control switch controlling said one relay switch,means responsive to predetermined operation of said energy supply meansfor controlling the other of said relay switches, and time intervalcontrol means operable, when preconditioned, to control operation ofsaid energy supply means to supply electrical energy to said electrodefor a predetermined period, said interval control means beingpreconditioned upon closure of said main switch and being renderedeffective to perform its controlling operation by opening of said mainswitch.

2. A burner control apparatus, comprising a gaseous fuel burner, meansto supply fuel to said burner, an electrically operable valve normallybiased to closed position and movable to closed position upondeenergization and controlling fuel flow through said supply means tosaid burner, ignition means for said burner, a circuit for said valve, arelay switch having an energizing circuit and controlling deenergizationof 'said ignition means, a main switch operable to open said energizingcircuit and the circuit of said valve, and means to supply current tosaid relay switch upon opening of said energizing circuit by said mainswitch thereby to hold said relay switch energized.

3. A burner control apparatus, comprising a gaseous fuel burner, meansto supply fuel to said burner, an electrically operable valve normallybiased to closed position and movable'to closed position upondeenergization and controlling fuel flow through said supply means tosaid burner, ignition means for said burner, a circuit for said valve, arelay switch having an energizing circuit and controlling deenergizationof said ignition means, a main switch operable to open said energizingcircuit and the circuit of said valve, and a condenser having acontrolled discharge and in shunt with the coil of said relay switch tosupply current to said relay switch upon opening of said energizingcircuit by said main switch thereby to hold said relay switch energized.

4. A burner control apparatus, comprising a gaseous fuel burner, meansto supply fuel to said burner, an electrically operable valve normallybiased to closed position and controlling fuel flow through said supplymeans to said burner, electric ignition means for said burner, a timermotor, means including a dominant switch and 2. normally open main relayswitch controlling both said valve and said ignition means, meansincluding a normally open valve-operating relay switch controlling saidvalve only, means including a double throw timer motor relay switch,means including a double throw snap-acting timer motor switch, saidtimer switches being in seriesparallel circuit with said motor, saidtimer motor relay switch having normally closed contacts in seriescircuit with normally open contacts of said snap-acting timer motorswitch, said timer motor relay switch having normally open contacts inseries circuit with normally closed contacts of said snap-acting timermotor switch, a can: operable by said motor and acting normally to holdclosed said normally closed snap-acting switch contacts, said dominantswitch being operable on closure to close said main relay switch and toclose said open timer motor relay switch contacts so that said ignitionmeans and said timer motor are energized, means operable upon occurrenceof ignition to close said valve-operating relay switch, said cam beingso constructed and arranged that upon movement by said motor. said camactuates said snap-acting switch to close said normally open snap-actingswitch contacts preparatory to restarting said timer motor and to opensaid normally closed snap-acting switch contacts thereby to stop saidtimer motor, said dominant switch acting when opened to "open said mainrelay switch and to reclose said normally closed timer relay switchcontacts thereby to reenergize said timer motor, a normally open camswitch controlling said ignition means only, and a cam driven by saidtimer motor and operable to close said cam switch, said last-named cambeing so constructed and arranged relative to said first-named cam as toopen said cam switch to deenergize said ignition means duringreenergization of said timer motor, said first-named cam acting tooperate said snap-acting switch to stop said timer motor sub;- sequentto opening of said cam switch.

5. A burner control apparatua comprising a gaseous fuel burner, aconduit for supplying fuelmally open contacts of said snap-acting timermotor switch, said timer motor relay switch having normally opencontacts in series circuit with normally closed contacts of saidsnap-acting timer motor switch, a cam operable by said motor and actingnormally to hold closed said normally closed map-acting switch contacts,a dominant switch operable on closure to close said main relay switchand to close said open timer motor relay switch contacts so that saidignition means and said timer motor are energized, means operable uponoccurrence of ignition to close said valve-operating relay switch, saidcam being so constructed and arranged that upon movement by said motor.said cam actuates said snap-acting switch to close said normally opensnap-acting switch contacts preparatory to restarting said motor and toopen said normally closed snapicting switch contacts thereby to stopsaid timer notor, said dominant switch acting when opened open said mainrelay switch thereby to deznergize said valve and said ignition meansand acting to reclose said normally closed timer relay switch contactsthereby to reenerglze said timer motor, a normally open cam switchcontrolling said ignition means only, and a time delay cam driven bysaid timer motor and operable subsequent to said reenergization of saidtimer motor first to close and then to open said cam switch to provide aperiod of operation of said ignition means, said first-named cam actingto operate said snap-acting switch to stop said timer motor subsequentto opening of said cam switch.

6. A burner controlling apparatus comprising a gaseous fuel burner,means for supplying fuel to said burner, an electromagnetic valve,normally biased to closed position, for controlling the supply of fuelthrough said supply means, electrical control means for controlling saidvalve to open position at times, electric ignition means for the fuelsupplied to said burner, means onerable to energize said ignition means,means responsive to a thermal change in one direction for energizingsaid electrical control means and for controlling said operable means,and means including said electrical control means and responsive to saidthermal responsive means when a desired temperature is reached in theopposite direction for energizing said ignition means for apredetermined period, said last-named means including means to delay theenergization of said ignition means by said last-named means.

7. A burner controlling apparatus comprising a gaseous fuel burner,means for supplying fuel to said burner, an electrically operable valve,normally biased to closed position, for controlling the supply of fuelthrough said supply means, electrical control means for controlling saidvalve to open position at times, electric ignition means for the fuelsupplied to said burner, means operable to energize said ignition means,an electric switch, means responsive to closure of said switch forenergizing said electrical control means and for controlling saidoperable means, and means including said electrical control means andresponsive to opening of said switch for energizing said ignition meansfor a predetermined period, said last-named means including means todelay the energization of said ignition means by said last-named means.

8. A burner controlling apparatus comprising a gaseous fuel burner, aconduit for supplylng fuel to the burner, an electrically operablevalve. normally biased to closed position, controlling flow through saidconduit, electric ignition means for the fuel supplied to said burner,means including a dominant switch operable when closed to energize saidignition means, means to energize said valve and responsive to operationof said ignition means, a timer motor, means to start said timer motorupon closure of said dominant switch, means operable by said timer motorto stop said timer motor upon predetermined running of said timer motorand to close a preparatory circuit for restartin said timer motor, meansto complete said preparatory circuit upon opening of said dominantswitch, cam means driven by said timer motor, and means operated by saidcam means upon predetermined running of said timer motor to reenergizesaid ignition means.

9. A burner controlling apparatus, comprising a gaseous fuel burner, aconduit for supplying fuel to the burner, an electrically operablevalve, normally biased to closed position, controlling flow through saidconduit, electric ignition means for the fuel supplied to the burner andhaving a controlling circuit, means including a dominant switch operablewhen closed to energize said ignition means circuit, a timer motor,parallel control circuits for said motor, a first double throw switchhaving normally closed contacts in one of said control circuits and opencontact in the other of said control circuits, at second double throwswitch having closed contacts in said other of said control circuits andopen contacts in said one of said control circuits, means operable onclosure of said dominant switch to open said first switch closedcontacts and to close said first switch open contacts to start saidmotor, a cam driven by said motor and operable upon predetermined motorrunning to open said second switch closed contacts to stop said motorand to close said second switch open contacts preparatory to reclosureof said first switch normally closed contacts upon opening of saiddominant switch, a second controlling circuit for energizing saidelectric ignition means and having a switch, and a cam driven by saidmotor upon restarting by the opening of said dominant switch andoperable upon predetermined motor running to open said last-named switchto stop said ignition means.

FRED B. AUBERT.

